<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>三栏布局</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        html,body{
            height: 100%;
        }
        header,footer{
            height: 100px;
            background-color: darkkhaki;
        }
        /* header{
            width: 100%;
            position: fixed;
            top: 0;
        }
        header::after{
            content: "aaaa";
            display: block;
            clear: both;
            visibility: hidden;
            width: 0;
            height: 0;
        } */
        section{
            height: calc(100% - 200px);
            background-color: rgb(217, 215, 112);
        }
        section nav,section aside{
            height: 100%;
            width: 100px;
            background: rgb(252, 250, 250);
            float: left;
        }
        section main{
            width: calc(100% - 200px);
            height: 100%;
            float: left;
        }
    </style>
</head>
<body>
    <header>Lorem ipsum, dolor sit amet consectetur adipisicing elit. Similique autem consequatur illum porro. Labore sapiente architecto, 
        pariatur ullam nisi ipsa eius expedita suscipit corrupti? Explicabo dolores nulla odit eligendi! Ipsam!</header>
    <section>
        <nav></nav>
        <main></main>
        <aside></aside>
    </section>
    <footer></footer>
</body>
</html>